1. Technical Field
The present technology relates to a pneumatic tire, and particularly to a pneumatic tire by which a useful and novel method for attaching a desired object, particularly an electronic device, to an inner surface of a pneumatic tire is realized.
2. Related Art
In recent years, various attempts at disposing objects having various functions on an inner surface of a pneumatic tire have been made.
For example, an attaching method has been proposed in which tire tags (radio frequency identification tags), chips, or the like are attached to an inner liner or the like of a green tire using a surface fastener such as a hook and loop fastener, a hook and hook fastener, or the like (Japanese Unexamined Patent Application Publication (translation of PCT application) No. 2005-517581).
Additionally, a pneumatic tire has been proposed in which a surface fastener is vulcanization bonded to a region corresponding to a tread portion of a tire inner surface, and a noise absorbing member is attached to the tire inner surface via the surface fastener (Japanese Unexamined Patent Application Publication No. 2006-44503A).
The surface fasteners proposed in Patent Documents 1 and 2 are preferable in that relatively strong engagement force is realized when attaching, and engagement on a surface can be achieved without slight misalignments when attaching becoming a problem.
However, with surface fasteners, a state in which the individual engaging elements of the surface fastener are engaged is not ideal due to the inner circumferential surface of the pneumatic tire being an annular, curved surface. With surface fasteners, portions of the edges and center portions become raised, and an amount of obtained engagement force varies (positional variation within the tire and variation from tire to tire). As a result, in some cases, the expected engagement force is not obtained. Additionally, partial physical deterioration and deterioration/declining over time of the engagement force of an entirety of the surface fastener accompanying the progression of the partial physical deterioration occurs as a result of repetitive deformation and compaction over an extended period of time caused by rotation at high speeds in a state of relatively elevated temperatures. This has led to difficulty in maintaining desired engagement force over an extended period of time.
As a result, surface fasteners could not be depended on to provide a high level of reliability for providing an object, having a special function for a certain purpose, on a tire inner surface.
In light of the foregoing, the present inventors have previously proposed a pneumatic tire having one side of a separatable pair of mechanical fasteners on a tire inner surface (Japanese Patent Application No. 2010-167839) as a pneumatic tire in which obtained engagement force is great and is essentially free of variations (positional variation within the tire and variation from tire to tire); the engagement force deteriorates/declines minimally over time due to extreme usage conditions including repetitive deformation and compaction over an extended period of time caused by tire rotation at high speeds in a state of relatively elevated temperatures; and the desired engagement force can be maintained over an extended period of time.
Here, the “mechanical fasteners” are a pair of fasteners configured so that two fasteners can be separated and can be mechanically re-engaged, and so that this engaging and separating can be freely repeated. Exemplary types of such mechanical fasteners are those known as “hooks” or “snaps”. Specific examples of products in the clothing industry and the like that are generally included as mechanical fasteners are snap buttons, ring snaps, ring hooks, American snaps, American hooks, eyelet hooks, spring hooks, and jumper hooks. Such mechanical fasteners differ from surface fasteners in that while an area of the engaging part of a surface fastener is unlimited in the entire area, the area of the engaging part of a mechanical fastener is small (e.g. preferably from about 1 to 115 mm2, or the like, and more preferably from about 4 to 90 mm2). In other words, the mechanical fastener is a point fastener. In other words, even when engaged at a small area of from about 1 to 115 mm2 or the like, due to a mechanical male-female structure or the like, strong engaging is achieved. The mechanical fasteners are made from a metal, rubber, synthetic resin material or the like. Fasteners known as “hooks” or “snaps” are known in the clothing industry and the like, but approaches using these mechanical fasteners in the tire industry have been superior from the perspectives of the degree of obtained engagement force, irregularities in size, and certainty of engaging operations.
FIG. 1 illustrates a state in which a first fastener of this pair of mechanical fasteners is attached to a tire inner surface. In FIG. 1, a first fastener 3A of a separatable pair of mechanical fasteners 3 is provided on a tire inner surface 2 of a pneumatic tire 1. 4 is a tread portion, 5 is a side wall portion, and 6 is a bead portion. The mechanical fasteners 3 are constituted by a pair of fasteners including a concave or female fastener 3A as illustrated in FIG. 9A, and a convex or male fastener 3B as illustrated in FIG. 9B. FIG. 9C illustrates a state in which this pair of fasteners is engaged.
Based on a tire side structure where the first fastener (3A) of the pair of mechanical fasteners is provided on the tire inner surface, a desired object having the second fastener (3B) of the pair of mechanical fasteners is disposed on an inner surface of the pneumatic tire by engaging with the fastener on the tire inner surface side, which pairs therewith.
However, a problem occurs due to the disposal method of the object on the tire inner surface using such mechanical fasteners, particularly when attaching an object having properties by which intended performance ceases to be displayed based on an attachment orientation thereof.
For example, in cases where a relatively small sized object is attached using only one fastener, there has been a problem where this small sized object rotates, having the fastener as a central axis of rotation, when in use (during tire traveling). When the attached object is an electronic device, this problem of the object rotating results in the direction of the antenna in the electronic device changing. This leads to the problem of instantaneous variations in receiving sensitivity. Moreover, this problem of the object rotating leads to a problem of accurate measurements becoming impossible in cases where the object is an acceleration sensor.
In order to prevent rotation, instead of using only one fastener to fix the object, always engaging/fixing the object at a plurality of locations using a plurality of fasteners has also been considered. However, in cases where the object to be fixed is small in size and the like, for example, in cases where the object is the electronic device described above and the like, there is a problem in that it is structurally difficult to engage/fix the object at a plurality of locations using a plurality of fasteners.
In light of the foregoing, an object of the present technology is to provide a pneumatic tire that is provided with a first fastener of a separatable pair of mechanical fasteners on a tire inner surface, wherein, even in cases where a desired object is engaged/fixed using only one fastener, the object does not rotate having the fastener as a central axis when the tire is in use.